Defect-induced optoelectronic response in single-layer group-VI transition-metal dichalcogenides

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Authors
Chow, Philippe K.
Issue Date
2015-12
Type
Electronic thesis
Thesis
Language
ENG
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Materials engineering
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Abstract
This thesis explores the behavior of defects in atomically-thin TMDC layers in response to optical stimuli using a combination of steady-state photoluminescence, reflectance and Raman spectroscopy at room-temperature. By systematically varying the defect density using plasma-irradiation techniques, an unprecedented room-temperature defect-induced monolayer PL feature was discovered. High-resolution transmission electron microscopy correlated the defect-induced PL with plasma-generation of sulfur vacancy defects while reflectance measurements indicate defect-induced sub-bandgap light absorption. Excitation intensity-dependent PL measurements and exciton rate modeling further help elucidate the origin of the defect-induced PL response and highlights the role of non-radiative recombination on exciton conversion processes.
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December 2015
School of Engineering
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Rensselaer Polytechnic Institute, Troy, NY
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